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<div class="titlepage"><div><div><h5 class="title">
<a name="asio.reference.ip__basic_resolver.async_resolve.overload3"></a><a class="link" href="overload3.html" title="ip::basic_resolver::async_resolve (3 of 6 overloads)">ip::basic_resolver::async_resolve
          (3 of 6 overloads)</a>
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<p>
            Asynchronously perform forward resolution of a query to a list of entries.
          </p>
<pre class="programlisting">template&lt;
    typename <a class="link" href="../../ResolveHandler.html" title="Resolve handler requirements">ResolveHandler</a>&gt;
<a class="link" href="../../asynchronous_operations.html#asio.reference.asynchronous_operations.automatic_deduction_of_initiating_function_return_type"><span class="emphasis"><em>DEDUCED</em></span></a> async_resolve(
    string_view host,
    string_view service,
    resolver_base::flags resolve_flags,
    ResolveHandler &amp;&amp; handler);
</pre>
<p>
            This function is used to resolve host and service names into a list of
            endpoint entries.
          </p>
<h6>
<a name="asio.reference.ip__basic_resolver.async_resolve.overload3.h0"></a>
            <span><a name="asio.reference.ip__basic_resolver.async_resolve.overload3.parameters"></a></span><a class="link" href="overload3.html#asio.reference.ip__basic_resolver.async_resolve.overload3.parameters">Parameters</a>
          </h6>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">host</span></dt>
<dd><p>
                  A string identifying a location. May be a descriptive name or a
                  numeric address string. If an empty string and the passive flag
                  has been specified, the resolved endpoints are suitable for local
                  service binding. If an empty string and passive is not specified,
                  the resolved endpoints will use the loopback address.
                </p></dd>
<dt><span class="term">service</span></dt>
<dd><p>
                  A string identifying the requested service. This may be a descriptive
                  name or a numeric string corresponding to a port number. May be
                  an empty string, in which case all resolved endpoints will have
                  a port number of 0.
                </p></dd>
<dt><span class="term">resolve_flags</span></dt>
<dd><p>
                  A set of flags that determine how name resolution should be performed.
                  The default flags are suitable for communication with remote hosts.
                </p></dd>
<dt><span class="term">handler</span></dt>
<dd>
<p>
                  The handler to be called when the resolve operation completes.
                  Copies will be made of the handler as required. The function signature
                  of the handler must be:
</p>
<pre class="programlisting">void handler(
  const asio::error_code&amp; error, // Result of operation.
  resolver::results_type results // Resolved endpoints as a range.
);
</pre>
<p>
                  Regardless of whether the asynchronous operation completes immediately
                  or not, the handler will not be invoked from within this function.
                  Invocation of the handler will be performed in a manner equivalent
                  to using <code class="computeroutput">asio::io_context::post()</code>.
                </p>
</dd>
</dl>
</div>
<p>
            A successful resolve operation is guaranteed to pass a non-empty range
            to the handler.
          </p>
<h6>
<a name="asio.reference.ip__basic_resolver.async_resolve.overload3.h1"></a>
            <span><a name="asio.reference.ip__basic_resolver.async_resolve.overload3.remarks"></a></span><a class="link" href="overload3.html#asio.reference.ip__basic_resolver.async_resolve.overload3.remarks">Remarks</a>
          </h6>
<p>
            On POSIX systems, host names may be locally defined in the file <code class="computeroutput">/etc/hosts</code>.
            On Windows, host names may be defined in the file <code class="computeroutput">c:\windows\system32\drivers\etc\hosts</code>.
            Remote host name resolution is performed using DNS. Operating systems
            may use additional locations when resolving host names (such as NETBIOS
            names on Windows).
          </p>
<p>
            On POSIX systems, service names are typically defined in the file <code class="computeroutput">/etc/services</code>.
            On Windows, service names may be found in the file <code class="computeroutput">c:\windows\system32\drivers\etc\services</code>.
            Operating systems may use additional locations when resolving service
            names.
          </p>
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<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2018 Christopher M. Kohlhoff<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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